Mojo: Add leak detection to mojo::embedder::test::Shutdown().

Don't hook up Init()/Shutdown() to our test harnesses yet, because
things blow up (we currently have singletons that will hold handles
across tests).

R=sky@chromium.org

Review URL: https://codereview.chromium.org/136793026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245605 0039d316-1c4b-4281-b951-d872f2087c98

mojo/system/core_impl.h

@@ -14,12 +14,17 @@
 #include "mojo/system/system_impl_export.h"
 
 namespace mojo {
-
 namespace system {
 
 class CoreImpl;
 class Dispatcher;
 
+// Test-only function (defined/used in embedder/test_embedder.cc). Declared here
+// so it can be friended.
+namespace internal {
+bool ShutdownCheckNoLeaks(CoreImpl*);
+}
+
 // |CoreImpl| is a singleton object that implements the Mojo system calls. All
 // public methods are thread-safe.
 class MOJO_SYSTEM_IMPL_EXPORT CoreImpl : public Core {
@@ -80,6 +85,8 @@ class MOJO_SYSTEM_IMPL_EXPORT CoreImpl : public Core {
                                  uint32_t num_bytes_read) OVERRIDE;
 
  private:
+  friend bool internal::ShutdownCheckNoLeaks(CoreImpl*);
+
   // The |busy| member is used only to deal with functions (in particular
   // |WriteMessage()|) that want to hold on to a dispatcher and later remove it
   // from the handle table, without holding on to the handle table lock.
@@ -145,7 +152,6 @@ class MOJO_SYSTEM_IMPL_EXPORT CoreImpl : public Core {
 };
 
 }  // namespace system
-
 }  // namespace mojo
 
 #endif  // MOJO_SYSTEM_CORE_IMPL_H_

mojo/system/embedder/embedder_unittest.cc

@@ -91,7 +91,7 @@ TEST_F(EmbedderTest, ChannelsBasic) {
                                            client_channel_info));
 #endif  // !defined(OS_WIN)
 
-  test::Shutdown();
+  EXPECT_TRUE(test::Shutdown());
 }
 
 // TODO(vtl): Test immediate write & close.

mojo/system/embedder/test_embedder.cc

@@ -5,22 +5,45 @@
 #include "mojo/system/embedder/test_embedder.h"
 
 #include "base/logging.h"
+#include "base/macros.h"
 #include "mojo/system/core_impl.h"
 
 namespace mojo {
+
+namespace system {
+namespace internal {
+
+bool ShutdownCheckNoLeaks(CoreImpl* core_impl) {
+  // No point in taking the lock.
+  if (core_impl->handle_table_.empty())
+    return true;
+
+  for (CoreImpl::HandleTableMap::const_iterator it =
+           core_impl->handle_table_.begin();
+       it != core_impl->handle_table_.end();
+       ++it) {
+    LOG(ERROR) << "Mojo embedder shutdown: Leaking handle " << (*it).first;
+  }
+  return false;
+}
+
+}  // namespace internal
+}  // namespace system
+
 namespace embedder {
 namespace test {
 
-void Shutdown() {
+bool Shutdown() {
   system::CoreImpl* core_impl = static_cast<system::CoreImpl*>(Core::Get());
   CHECK(core_impl);
   Core::Reset();
 
-  // TODO(vtl): Check for leaks, etc.
-
+  bool rv = system::internal::ShutdownCheckNoLeaks(core_impl);
   delete core_impl;
+  return rv;
 }
 
 }  // namespace test
 }  // namespace embedder
+
 }  // namespace mojo

mojo/system/embedder/test_embedder.h

@@ -13,8 +13,10 @@ namespace test {
 
 // This shuts down the global, singleton instance. (Note: "Real" embedders are
 // not expected to ever shut down this instance. This |Shutdown()| function will
-// do more work to ensure that tests don't leak, etc.)
-MOJO_SYSTEM_IMPL_EXPORT void Shutdown();
+// do more work to ensure that tests don't leak, etc.) Returns true if there
+// were no problems, false if there were leaks -- i.e., handles still open -- or
+// any other problems.
+MOJO_SYSTEM_IMPL_EXPORT bool Shutdown();
 
 }  // namespace test
 }  // namespace embedder